Assessment of macrogeographical genetic variations in jatropha curcas l in india using allozyme and rapd markers

Abstract

Jatropha curcas L., an exotic introduced in to India by Portuguese about 500 years ago, was assessed for its genetic base in the country as a step to initiate breeding programmes. Genetic diversity of 56 accessions of Jatropha estimated from allozymes and from Random Amplified Polymorphic DNA (RAPDs) revealed eighteen allozyme loci and 120 RAPD markers. According to allozyme data, species genetic diversity (p = 26.67%, A = 1.533 and He =0.205), was low. Inbreeding coefficients suggest that populations are structured in genetic neighborhoods. The RAPDs also showed similar levels of genetic diversity (p = 35.73% and He = 0.181) at the species level. Nei’s genetic distances estimated both from allozymes and RAPDs indicated low differentiation among populations. No significant associations among genetic and geographical variables were observed, suggesting that such low genetic variation in this allogamous species could be due to the few introductions that have spread across the country primarily, through vegetative propagation. The species has not been improved for productivity and thus naturally occurring unadapted populations are a result of the few initial introductions.